Pathology.—RB-ILD is a smoking-related disease characterized by inflammation (predominantly by macrophages) of the respiratory bronchioles and peribronchiolar alveoli (5), sometimes with elements of or overlap with nonspecific and desquamative interstitial pneumonias (114).
CT scans.—RB-ILD typically manifests as extensive centrilobular micronodules and patchy ground-glass opacity corresponding to macrophage-rich alveolitis (Fig 60), with or without fine fibrosis (115,116). It is often accompanied by bronchial wall thickening and minor centrilobular emphysema. Areas of air trapping reflect a bronchiolitic component. [Fleischner Society]